I agree that there is very little "apparent" differences. There are however supposedly enhancements to performance but I believe it was mostly to bring the OS in line with the Tablets so that Developers could write apps with less fragmentation needing to be addressed. That's my take on it, but I'm sure others can add valuable perspective.
As for the version that was pulled, it's now being pushed again, same version, no apparent changes to the OS itself. I am aware of this because a second MAXX which I have and which I didn't do the side-load upgrade on, just completed an OTA download of the upgrade to KitKat by itself last night. I ran the upgrade and it booted completely functional afterwards, updating all installed apps in the process.
t appears that the only changes may be to the Recovery process which allowed flashing. It is my understanding that the Jelly Bean Recovery is incompatible with the flashing process required for KitKat, so there was also a KitKat Recovery update in the original version (and also in the "pulled" version), however there was some form of incompatibility or inconsistency with the replacement Recovery that caused many phones to brick while doing the upgrade. It is expected that they've nailed down what happened on that first round of pushes and it's been resolved now (hopefully), and that all OTA upgrades will now go off without a hitch.
I for one downloaded and side-loaded the update and it went off without a hitch, but it's very strange in the way it goes down, because you actually have to flash it twice. The first flash appears to fail, says it's incompatible, but what's really happened is it has replaced the Recovery from Jelly Bean with the one for KitKat. When you flash the second time it completes successfully - or at least it does/did with everyone I am aware of that dared to try it, including me.
